Chapter 1 Flashcards
Introduction
What is a Software?
Computer programs and associated documentation that may be developed for a particular customer, or for a general market.
What are the Essential Attributes of a Good Software?
Maintainability – Software should be written in such a way so that it can evolve to meet the changing needs of customers.
Dependability and security – Software dependability includes a range of characteristics including reliability, security and safety. Dependable software should not cause physical or economic damage in the event of system failure. Malicious users should not be able to access or damage the system.
Efficiency – Software should not make wasteful use of system resources such as memory and processor cycles. Efficiency therefore includes responsiveness, processing time, memory utilization, etc.
Acceptability – Software must be acceptable to the type of users for which it is designed. This means that it must be understandable, usable and compatible with other systems that they use.
Describe Generic Products.
Stand – alone systems.
Targeted and sold to any customer who wishes to buy them.
Ex., PC Software (databases, project management tools), software for specific markets.
The organization that develops the software, controls the software specifications.
Describe Customized Products.
Software that is specifically designed and developed for a particular person.
Ex., embedded control systems, traffic monitoring systems.
The organization that is buying the software controls and develops the software specifications.
What is Software Engineering, and why is it important?
Software engineering – is an engineering discipline that is concerned with all aspects of software production from the early stages of system specification through to maintaining the system after it has gone into use.
Engineering discipline – Using appropriate theories and methods to solve problems bearing in mind organizational and financial constraints.
All aspects of software production – Not just technical process of development, also project management and the development of tools, methods etc. to support software production.
Important for two reasons:
1) Society relies on advanced software systems. We need to be able to produce reliable / trustworthy systems economically / quickly.
2) It is usually cheaper in the long run rather than just write the programs.
Describe Software Costs.
- Often dominate computer system costs.
- The costs of software on a PC are often greater than the hardware cost.
- Software costs more to maintain than it does to develop.
- For systems with a long life, maintenance costs may be several times development costs.
- Software engineering is concerned with cost-effective software development.
Describe Software process activities.
Software Specification, where customers and engineers define the software that is to be produced and the constraints on its operation.
Software Development, where the software is designed and programmed.
Software Validation, where the software is checked to ensure that it is what the customer requires.
Software Evolution, where the software is modified to reflect changing customer and market requirements.
What are the general issues that affect most software?
Heterogeneity – Increasingly, systems are required to operate as distributed systems across networks that include different types of computer and mobile devices.
Business and Social change – Business need to be able to change their existing software and to rapidly develop new software.
Security and Trust – As software is intertwined with all aspects of our lives, it is essential that we can trust that software.
Scale – Software has to be developed across a very wide range of scaled, form very small embedded systems, to Internet – Scale systems.
Describe the application types.
Stand-alone applications – These are application systems that run on a local computer, such as a PC. They include all necessary functionality and do not need to be connected to a network.
Interactive transaction-based applications – Applications that execute on a remote computer and are accessed by users from their own PCs or terminals. These include web applications such as e-commerce applications.
Embedded control systems – These are software control systems that control and manage hardware devices. Numerically, there are probably more embedded systems than any other type of system.
Batch processing systems – These are business systems that are designed to process data in large batches. They process large numbers of individual inputs to create corresponding outputs.
Entertainment systems – These are systems that are primarily for personal use and which are intended to entertain the user.
Systems for modeling and simulation – These are systems that are developed by scientists and engineers to model physical processes or situations, which include many, separate, interacting objects.
Data collection systems – These are systems that collect data from their environment using a set of sensors and send that data to other systems for processing.
Systems of systems – These are systems that are composed of a number of other software systems.
Describe the software engineering fundamentals.
Systems should be developed using a managed and understood development process.
Dependability and performance are important for all types of systems.
Understanding and managing the software specification and requirements are important.
Where appropriate, you should reuse software that has already been developed rather than write new software.
What can you write about software engineering and the web?
- The Web is now a platform for running application and organizations are increasingly developing web-based systems rather than local systems.
- Web services allow application functionality to be accessed over the web.
- Cloud computing is an approach to the provision of computer services where applications run remotely on the ‘cloud’.
Web – Based Software Engineering:
Web-based systems are complex distributed systems but the fundamental principles of software engineering discussed previously are as applicable to them as they are to any other types of system.
The fundamental ideas of software engineering, discussed in the previous section, apply to web-based software in the same way that they apply to other types of software system.
What are some software engineering ethics?
- Software engineering involves wider responsibilities than simply the application of technical skills.
- Software engineers must behave in an honest and ethically responsible way if they are to be respected as professionals.
- Ethical behavior is more than simply upholding the law but involves following a set of principles that are morally correct.
Write about the issues of professional responsibility.
Confidentiality – Engineers should normally respect the confidentiality of their employers or clients irrespective of whether or not a formal confidentiality agreement has been signed.
Competence – Engineers should not misrepresent their level of competence. They should not knowingly accept work which is out of their competence.
Intellectual Property Rights – Engineers should be aware of local laws governing the use of intellectual property such as patents, copyright, etc. They should be careful to ensure that the intellectual property of employers and clients is protected.
Computer Misuse – Software engineers should not use their technical skills to misuse other people’s computers. Computer misuse ranges from relatively trivial (game playing on an employer’s machine, say) to extremely serious (spreading viruses).
